1. Field of the Invention
The present invention relates to a data processing device including so-called microcomputer for digital signal processing for the purpose of circuit or function control in the copier or the like, and more particularly to a data processing device provided with analog-digital converting function for input analog signals and digital-analog converting function for obtaining output analog signals.
2. Description of the Prior Art
In the data processing device of the above-mentioned sort, comprising so-called microcomputer for function control of the copier or the like, in which the input data from an external sequence controller etc. are processed in a digital circuit according to predetermined programs, it is generally necessary to convert input signals, if in analog form, into digital signals, and to convert the output digital signals into analog signals if such analog output data are desired.
The conventional data processing device of this sort is generally used in combination, according to the necessity, with a separate analog-digital converter for generating signals required for digital processing from input analog signals and a separate digital converter for obtaining output analog signals corresponding to the results of the digital processing. Such converter or converters may be incorporated in the data processing device itself, but such incorporation with the conventional circuitry merely includes the ordinary converters and the ordinary data processing device on a same chip, thus leading inevitably to a complicated circuit structure. Consequently such conventional device is inevitably large in size and involves an increase in the hardware structure, thus giving rise to an insufficient reliability.